The Collaborative International Dictionary of English v.0.48:

Gall \Gall\ (g[add]l), n.[OE. galle, gal, AS. gealla; akin to D.
   gal, OS. & OHG. galla, Icel. gall, SW. galla, Dan. galde, L.
   fel, Gr. ?, and prob. to E. yellow. [root]49. See Yellow,
   and cf. Choler]
   1. (Physiol.) The bitter, alkaline, viscid fluid found in the
      gall bladder, beneath the liver. It consists of the
      secretion of the liver, or bile, mixed with that of the
      mucous membrane of the gall bladder.
      [1913 Webster]

   2. The gall bladder.
      [1913 Webster]

   3. Anything extremely bitter; bitterness; rancor.
      [1913 Webster]

            He hath . . . compassed me with gall and travail.
                                                  --Lam. iii. 5.
      [1913 Webster]

            Comedy diverted without gall.         --Dryden.
      [1913 Webster]

   4. Impudence; brazen assurance. [Slang]
      [1913 Webster]

   Gall bladder (Anat.), the membranous sac, in which the
      bile, or gall, is stored up, as secreted by the liver; the
      cholecystis. See Illust. of Digestive apparatus.

   Gall duct, a duct which conveys bile, as the cystic duct,
      or the hepatic duct.

   Gall sickness, a remitting bilious fever in the
      Netherlands. --Dunglison.

   Gall of the earth (Bot.), an herbaceous composite plant
      with variously lobed and cleft leaves, usually the
      Prenanthes serpentaria.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

gall-of-the-earth \gall-of-the-earth\ n.
   A common perennial herb (Nabalus serpentarius) widely
   distributed in southern and eastern U. S., having drooping
   clusters of pinkish flowers and thick basal leaves suggesting
   a lion's foot in shape; sometimes placed in the genus
   Prenanthes.

   Syn: lion's foot, gall of the earth, Nabalus serpentarius,
        Prenanthes serpentaria.
        [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Rattlesnake \Rat"tle*snake`\ (r[a^]t"t'l*sn[=a]k`), n. (Zool.)
   Any one of several species of venomous American snakes
   belonging to the genera Crotalus and Caudisona, or
   Sistrurus; sometimes also called rattler. They have a
   series of horny interlocking joints at the end of the tail
   which make a sharp rattling sound when shaken. The common
   rattlesnake of the Northern United States (Crotalus
   horridus), and the diamondback rattlesnake (also called
   diamondback rattler, and diamondback) of the South and
   East (Crotalus adamanteus) and West (Crotalus atrox), are
   the best known. See Illust. of Fang.
   [1913 Webster +PJC]

   Ground rattlesnake (Zool.), a small rattlesnake (Caudisona
      miliaria or Sistrurus miliaria) of the Southern United
      States, having a small rattle. It has nine large scales on
      its head.

   Rattlesnake fern (Bot.), a common American fern
      (Botrychium Virginianum) having a triangular decompound
      frond and a long-stalked panicle of spore cases rising
      from the middle of the frond.

   Rattlesnake grass (Bot.), a handsome American grass
      (Glyceria Canadensis) with an ample panicle of rather
      large ovate spikelets, each one composed of imbricated
      parts and slightly resembling the rattle of the
      rattlesnake. Sometimes called quaking grass.

   Rattlesnake plantain (Bot.), See under Plantain.

   Rattlesnake root (Bot.), a name given to certain American
      species of the composite genus Prenanthes (Prenanthes
      alba and Prenanthes serpentaria), formerly asserted to
      cure the bite of the rattlesnake. Called also lion's
      foot, gall of the earth, and white lettuce.

   Rattlesnake's master (Bot.)
   (a) A species of Agave (Agave Virginica) growing in the
       Southern United States.
   (b) An umbelliferous plant (Eryngium yuccaefolium) with
       large bristly-fringed linear leaves.
   (c) A composite plant, the blazing star (Liatris
       squarrosa).

   Rattlesnake weed (Bot.), a plant of the composite genus
      Hieracium (Hieracium venosum); -- probably so named
      from its spotted leaves. See also Snakeroot.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Prenanthes serpentaria
    n 1: common perennial herb widely distributed in the southern
         and eastern United States having drooping clusters of
         pinkish flowers and thick basal leaves suggesting a lion's
         foot in shape; sometimes placed in genus Prenanthes [syn:
         lion's foot, gall of the earth, Nabalus serpentarius,
         Prenanthes serpentaria]